The present invention is directed to a pyridine-soluble extract of a microorganism which, when combined with cell wall skeleton (CWS), provides a pharmaceutical composition possessing anti-animal tumor properties.
Bacteria such as Corynebacterium parvum have been the subject of experimental work to isolate and characterize the component responsible for inducing inhibition of tumor growth [see, for example, Anti Tumor Activity and Lymphoreticular Stimulation Properties of Fractions Isolated from C. parvum; Cantrell, et al, Cancer Research 39, pgs. 3554-3563 (September, 1979)]. Apart from anti-tumor activity, C. parvum has shown to be a potent stimulator of the lymphoreticular system resulting in undesirable increases in spleen and liver weights and blastogenesis. Applicant has discovered that a pyridine-soluble extract of microorganism possesses potent anti-animal tumor properties without the undesirable toxic effects associated with the prior art products.
Cell wall skeleton is essentially cell wall which has had much of the protein and lipids normally found in the cell wall removed. It is a polymeric mycolic acid arabinogalactan mucopeptide containing remnants of trehalose mycolates ("P3") and undigested tuberculoproteins. Cell wall skeleton is obtained from any microorganism including, but not limited to, M.smegmatis, M.phlei, Nocardia rubra, Nocardia asteroides, Corynebacterium diphtheria, Corynebacterium parvum, M.kansasii, M.tuberculosis (Strain H 37 RV and Ayoma B), and M.bovis Strain BCG. Additionally, cell wall skeleton may be obtained from such other microorganisms as E.coli, B.abortus and Coxiella burnettii.
Cell wall skeleton may be produced by first growing and harvesting bacteria such as M.bovis Strain BCG (Bacillus Calmette - Guerin). The resulting whole cell residue is processed through a cell fractionator [Ribi Cell Fractionator (Sorvall, Model RF-1)] which disrupts the cells, separating the outer envelope or cell wall from the protoplasmic impurities. The resulting cell walls are then subjected to a series of solvent extractions and enzymatic treatments (e.g., trypsin and/or chymotrypsin) to give purified cell wall skeleton.
It is, therefore, an object of the present invention to provide a pharmaceutical composition containing a pyridine-soluble extract of a microorganism in combination with cell wall skeleton.
It is another object of the invention to provide a method of producing the pyridine-soluble extract of a microorganism.
It is still another object of the invention to provide a method of treating tumors in warm blooded animals using the composition containing the pyridine-soluble extract of a microorganism and cell wall skeleton.